One area of research beneficial to machine automation concerns automatic identification and discrimination of materials, particularly without contact to the material. For example, in robotic assembly or sorting plants, it can be important to identify materials or parts by optical means based on their material properties for assembling or sorting purposes.
In this context, it has been considered to measure statistics of a speckle pattern, to assist in a non-contact identification of a material or estimation of material properties thereof. A speckle pattern results from interference of light waves scattered by a material when illuminated by a light source (such as a laser) with controlled coherence properties.